/*
 * @Author: funlee
 * @Email: i@funlee.cn
 * @Date: 2018-01-10 23:45:33
 * @Last Modified time: 2018-01-10 23:45:33
 * @Description: 箭头 
 */
window.onload = function () {
  var canvas = document.querySelector('.canvas')
  var ctx = canvas.getContext('2d')

  ctx.strokeStyle = 'Hotpink'
  ctx.lineWidth = 4
  ctx.moveTo(40, 60)
  ctx.lineTo(100, 60)
  ctx.lineTo(100, 30)
  ctx.lineTo(150, 75)
  ctx.lineTo(100, 120)
  ctx.lineTo(100, 90)
  ctx.lineTo(40, 90)
  ctx.lineTo(40, 60)
  ctx.stroke()

}